Phosphinylmethylphosphinic acids



United States Patent 3,332,986 PHOSPHINYLMETHYLPHOSPHINIC ACIDS BurtonPeter Block, Wayne, Ivan C. Popolf, Ambler,

James Ping King, Elkins Park, and Ludwig K. Huber, Philadelphia, Pa.,assignors to Pennsalt Chemicals Corporation, Philadelphia, Pa., acorporation of Pennsylvania No Drawing. Filed June 24, 1963, Ser. No.290,233 Claims. (Cl. 260-500) This invention relates to compounds ofphosphorus which have the structure where R R and R are hydrocarbonalkyl and hydrocarbon aryl groups containing from one to ten carbonatoms. The compounds of this invention are useful as chelating agentswhich agents are known to be of-value in analytical procedures, as dyesand pigments, as intermediates, as catalysts and for various otherapplications.

The compounds of the invention are prepared in two steps by firstreacting at elevated temperature (say at about 100 to 175 C.) achloromethylphosphine oxide of structure R R P(O)CH Cl with aphosphonite diester of structure R P(OR where R R and R are as definedabove and R is a lower alkyl group, and then hydrolyzing the estersobtained under acid conditions.

The chloromethylphosphine oxide reactants may be made by the processdescribed by Kabachnik and Shepeleva (C.A. 49:843i 1955). When R and Rof the chloromethylphosphine oxide are different, a preferred method forthe preparation is that which involves the reaction of a Grignardreagent with a compound of structure R (ClCH )P(O)C1; viz:

R1 P-CHzCl RzMgX i -omol I O1 Rn Chloromethylphosphine oxides useful toprepare the compounds of this invention will includediphenylchloromethylphosphine oxide, methylphenylchloromethylphosphineoxide, dimethylchl-oromethylphosphine oxide,methylethylchloromethylphosphine oxide, dibutylchloromethylphosphineoxide, phenylhexylchlor-omethylphosphine oxide,methyltolylchloromethylphosphine oxide, dinaphthylchloromethylphosphineoxide, phenylnaphthylchloromethylphosphi-ne oxide,

.naphthylethylchloromethylphosphine oxide,

phenyloctylchloromethylphosphine oxide, didecylcloromethylphosphineoxide, dit-olylchloromethylphosphine oxide, and the like.

Diphenylchloromethylphosphine oxide is prepared by the method ofKabachnik and Shepeleva referred to above.

r 3,332,986 Patented July 25, 1967 A mixture of 10.0 g. (0.04 mole) of(C H P(0)CH Cl and 7.92 g. (0.04 mole) of C H P(OC H is placed in a 250ml. three-necked flask equipped with a reflux condenser, nitrogen inlettube, and thermometer well and containing a magnetic stirring bar. Themixture is slowly heated in an oil bath with stirring and under a slowstream of nitrogen. At C. the solution clears and vigorous evolution ofC H Cl is observed above 160 C. accompanied by a rapid increase to 175C. The reaction temperature is maintained between 170 and 180 C. for aperiod of two hours. After the reaction product has cooled to roomtemperature under nitrogen, it is triturated three times with 50-ml.portions of chilled diethyl ether. There results 11.6 g. of white solidmelting at 114-118 C. which is purified by distillation at 240 C./ 0.2mm. Hg to give a melting point of 122-124 C. Calcd. for C H O P: C,65.61; H, 5.77; P, 16.12. Found: C, 65.74; H, 5.74; P, 15.96. This solidester is hydrolyzed by refluxing it in ml. of 2 M HCl for 7.5 hours. TheHCl solution is then distilled off, and benzene is distilled from theresidue until a clear solution results. After the solution standsovernight, 6.7 g. (47% yield) of a white solid melting at 125-130 C. isisolated. Repeated recrystallization of this solid from toluene (oracetonitrile) yields a white crystalline solid with a melting point of-131" C. The infrared spectrum of this product shows PC H P- O, and P-OHabsorptions and is consistent with the structure Analysis.CalCd. forc19H1 03P2: C, H, P, 17.39; neutral equivalent 356. Found: C, 63.90; H,5,31;P,17.45;n.e.355.

Example 2 Phenylmethylchloromethylphosphine oxide is prepared in twosteps. Using the method of Kabachnik and Shepeleva,dichlorophenylphosphine is reacted with para-formaldehyde to yieldchloro-chloromethylphenylphosphine which is then reacted with methylmagnesium bromide to give phenylmethylchloromethylphosphine oxide.

, A mixture of 10.0 g. (0.053 mole) of C H (CH P (O CH CI and 10.5 g.(0.053 mole) of C H P(OC H is treated in the same Way as the mixture inExample 1. A clear solution forms at 104 C. and ethyl chloride isliberated. Similar work up give 8.5 g. (51.6% yield) of crude prod uctmelting at 205-210 C. Recrystallization from benzene yields a productwith a melting point of 206-208 C. The infrared spectrum is quitesimilar to that of but has a band at 7.7,u which is due to the P-CHgroup.

Calcd. for C I-I O P C, 57.20; H, 5.45; P, 21.10; neutral equivalent,294. Found: C, 56.86; H, 6.10; P, 21.13; neutral equivalent, 292.

Example 3 3 Jrior to hydrolysis. Work up as in Example 1 gives 11.5 g.(78% yield) of crude product melting at 112-140 C. Repeatedrecrystallization from acetonitrile gives a white :rystalline solidmelting at 143145 C. Its infrared specrum is very similar to that of(CGH5(CH3)P(O)CH2P(CGH5)(O)OH Calcd. for C H O P C, 46.60; H, 6.04; P,26.70; neural equivalent, 232. Found: C, 46.70; H, 6.16; P, 26.89;ieutral equivalent, 230.

Example 4 Instead of using phenylchloromethylphosphine oxide 11 Example1, dinaphthylchloromethylphosphine oxide is lsed with essentially thesame results yielding a product raving the structure 1 ll (C101)2PCHrPOH CflHfi Example 5 If in Example 1 the diester C H P(OC H isreplaced vith C H P(OC H the reaction proceeds in a similar manner toyield a product of structure In a similar manner, whenmethyltolylchloromethylhosphine oxide is used in the procedure ofExample 1 a roduct of structure iobtained.

As is evident from the above examples, compounds of re invention arecolorless crystalline solids which melt harply at temperatures on theorder of 100 to 200 C. nd higher. The compounds are soluble inhydrocarbon olvents such as benzene, toluene and xylene from which heyare readily crystallized. Likewise they are soluble in olar materialssuch as acetonitrile, propionitrile and the ike, ketones such asmethylethyl ketone, alcohols such as aethanol, isopropanol, etc., andthe like. As indicated, the ompounds are useful chelating agentsinvolving the oxy nd hydroxy portions of the molecule. Examplesillustratig the chelating capabilities of the compounds follow:

Example 7 A solution of 2.3 g. (0.0063 mole) of vnd 0.64 g. (0.0028mole) of Zn(OCOCH '2H O in 0 ml. of ethanol is refluxed for 3.5 hours.Removal of ac solvent leaves a viscous oil which yields a whitepreipitate upon treatment with 40 m1. of diethyl ether. This roduct isrecrystallized from an ethanol-benzene mixture 3 give 2.0 g. (92% yield)of a white solid melting at 265- 73 C. Initial weight loss, which may besublimation, ccurs at about 300 C. on the thermobalance.

Calcd. for (C6H5 ZZH: C, 8.80; H, 4.39; P, 16.0; Zn, 8.2; mol. wt. 775.Found: 1, 58.67; H, 4.75; P, 15.32; Zn, 8.4; mol. wt. 1401 (inhloroform). The analysis and molecular weight deteriination show thatthe product obtained has the structure CBHB CGHE CIIHB CaH 0 115 /O CuHsCqH5 which embodies a significant amount of chelation in the molecule.It is this chelation which contributes to the improved thermal stabilityof the molecule as is evident from the fact that it decomposes 100 C.higher than zinc acetylacetonate.

Example 8 A mixture of 2.0 g. (0.0068 mole) of and 0.74 g. (0.0034 mole)of Zn(OCOCH -2H O in 60 ml. of benzene is refluxed for three hours. Theoily residue left after the benzene is distilled off is added to 49 ml.of n-hexane. The resulting precipitate is dissolved in chloroform andreprecipitated with n-hexane. Yield is 2.1 g. of a white solid meltingat 135160' C. and soluble in most solvents.

Calcd. for C H O P Zn: C, 51.55; H, 4.61; P, 19.05; Zn, 10.0; mol. wt.651. Found: C, 51.61; H, 5.10; P, 18.69; C, 50.81; H, 4.99; P, 20.05;Zn, 10.5; mol. wt. 1302.

Example 9 A mixture of 4.4 g. (0.015 mole) of s 5( 3) z s 5) and 1.58 g.(0.0045 mole) of CI'(CH3COCHCOCH3)3 in ml. o-dichlorobenzene is refluxedfor 12 hours. The course of the reaction is followed by detecting theacetylacetonate liberated. The reaction product is subjected todistillation to strip off most of the solvent, and the viscous residueis dissolved in 70 ml. of benzene. The benzene solution is filtered, andthe filtrate is evaporated to a volume of 30 ml. to which 200 ml. ofpetroleum ether is added, resulting in instant precipitation of a greensolid (4.0 g.). A sample of 1.84 g. of the solid product is dissolved in10 ml. of chloroform. The chloroform solution is poured into an A1 0column which is eluted with chloroform and absolute ethanol,respectively. Two solids recovered from chloroform and ethanol solutionshave softening ranges of 210234 C. and 2l02l8 C. respectively. Initialweight losses of these compounds occur at about 330 and 350 C.

Calcd. for [C H (CH )P(O)CH P(O)(C H )O] Cr: C, 54.02; H, 4.84; P,19.98; Cr, 5.59. Found: C, 53.83; H, 5.38; P, 17.37; Cr, 5.5. C, 53.55;H, 4.86; P, 17.69; Cr, 5.7.

Example 10 If instead of using C H P(OC H in Example 3, CH P(OC H isused, the compound of structure is obtained in good yield.

It will be understood that numerous changes may be made from the abovedescription and examples without departing from the spirit and scope ofthe invention.

We claim:

1. Compounds of structure where R R and R are selected from the groupconsisting of hydrocarbon alkyl and aryl containing from one to tencarbon atoms.

2. A compound as in claim 1 where R R and R are phenyl radicals.

3. A compound as in claim 1 where R and R are phenyl and R is methyl.

4. A compqund as in claim 1 Where R and R are OTHER REFERENCES methyland R 1s phenyl. Frank: Chem. Reviews (1961 pp. 293, 411.

COmPOUIId as clam 1 where R2 and R3 are Kabachnik et aL: Chem.Abstracts, vol. 49, 1955, p. me y 843.

References Clted 5 Kosolapotf: Organophosphorus Compounds (1950), UNITEDSTATES PATENTS pp. 121, 122, 139.

2,634,288 4/ 1953 Boyer et a1. 260-932 V 1 3,161,687 12/1964 Garner260606.5 LEON Examme" 3,256,370 6/1966 Fitch et a1. 260-500 J. E. EVANS,Assistant Examiner.

1. COMPOUNDS OF STRUCTURE